FWIW...These flow numbers are right off their website.
Using the TFS #1 cam that I am running
adv 275*,221* @ .050 with .312 lift at the cam,.499 lift with 1.6 rockers
adv 279*, 225* @.050 with .319 lift at the cam,.510 lift with 1.6
Now in my combo a move to 1.7 rockers on the intake would give me .530 lift on the intake and increase 'effective' .050 duration by adding the theoretical 1-3* would make the intake side act like a 223* at .050 duration.
It can help get more hp from an exhuast biased set of heads like mine.With out stepping to a full blown custom cam.A custom cam would be cheaper than buying 2 sets of rockers
The only deal with increasing the intake lift is piston to valve claerance.
If the 1.7's will clear on the intake,run'em.Don't expext 50 hp from this,you MAY get 10hp.The unported GT40 head is not as biased on the exhaust side as my worked E7's.Intake is about the same.The bias is the intake to exhaust flow,70-75% is a good number.Mine are in the 80%+ range and MAY respond to this .
I would spring for a custom ground cam (~$300),rather than play with $400 worth of rockers.BUT,if you have both ratios,by all means try it!
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